In areas at risk of explosion, such as in coal mining, there are now similarly high automation ambitions as above ground. In the case of machine control and monitoring of mobile machines which are used in areas at risk of explosion, centrally arranged control consoles are generally used which are positioned in areas in which there are no problems with protection against explosion. In order to be able to control and monitor even complex automation sequences from above-ground control consoles, for example, a large number of different sensors and actuators, including test and diagnosis systems, are needed which have to be used in the area which is at risk of explosion. The high demands on productivity and reliability and also the evermore frequent application of powerful field bus protocols, for example, places ever greater demands on the structure ability and performance of the network infrastructure for communication between and control of the individual machine groups.
Ordinary network infrastructures for control systems for mobile machines used in areas at risk of explosion comprise a single, central controller. This individual controller controls and monitors all machine functions and controls the flow of information and data in the network. All input and output signals and also the sensor and actuator systems are captured and controlled directly by the central controller. This requires complex and therefore error-prone wiring of the individual appliance to the central unit. If the central controller fails, there is the risk that the entire communication or control function within the network may become inoperational.
The protection against explosion which is required in mining means that, in a network for explosive area, the network is divided into inherently safe network participants, which meet the stringent requirements on inherent safety for the respective protection against explosion, and not inherently safe network participants, which are therefore arranged in pressure-resistant housings, the pressure-resistant housings being used to ensure that the network participants which are not approved without the pressure-resistant housing can nevertheless be used in the area at risk of explosion. This separation between not inherently safe and inherently safe network participants in combination with the star-shaped orientation of the network increases the wiring complexity considerably.